A digital image's quality can be improved by enhancing the image's edge. Conventional methods of image edge enhancement often require an interpolation operation of an image to obtain a full color RGB image followed by a second-order Laplace operation and edge trend specific operation of the full color RGB image to enhance the image's edge. These methods are not only computationally expensive, but also require a large amount of memory space, e.g., a pre-storage of two to four rows of RGB data would occupy six to twelve rows of static random access memory (SRAM).